CN113174992A

CN113174992A - Comprehensive treatment and reinforcement method for collapse of stratum around marine deep-water inclined pile

Info

Publication number: CN113174992A
Application number: CN202110475861.5A
Authority: CN
Inventors: 罗承浩; 郭琼玲; 孔秋平; 许万强; 许万洪; 罗发锟; 郑添寿; 张强; 邱维衍
Original assignee: Fujian Yongqiang Soil Co ltd
Current assignee: Fujian Yongqiang Soil Co ltd
Priority date: 2021-04-29
Filing date: 2021-04-29
Publication date: 2021-07-27
Anticipated expiration: 2041-04-29
Also published as: CN113174992B

Abstract

The invention discloses a comprehensive treatment and reinforcement method for collapse of the surrounding stratum of a marine deep-water inclined pile, which adopts various means such as inclined hole grouting, inclined hole jet grouting, pile stirring and the like to form an integrated new composite foundation to reinforce the soil body around the pile, has obvious effect and quality on the collapse treatment of the surrounding stratum of the marine deep-water inclined pile, effectively ensures the safe and smooth operation of subsequent pile foundation construction, greatly reduces the construction period and economic loss, effectively ensures the bearing capacity and stability of the foundation of the marine deep-water inclined pile, and avoids the occurrence of potential safety hazards.

Description

Comprehensive treatment and reinforcement method for collapse of stratum around marine deep-water inclined pile

Technical Field

The invention relates to the technical field of engineering construction, in particular to a comprehensive treatment and reinforcement method for stratum collapse around an offshore deep-water inclined pile.

Background

Pile cap foundation is a form of foundation structure, and is a deep foundation consisting of piles and pile caps (called caps for short) connecting pile tops, called pile foundations for short. If the pile body is completely buried in the soil and the bottom surface of the bearing platform is contacted with the soil body, the pile body is called a low pile bearing platform foundation; if the upper part of the pile body is exposed out of the ground and the bottom of the bearing platform is above the ground, the pile body is called a high pile bearing platform foundation. The high pile cap foundation is widely applied to offshore wind power, large-span bridges, wharfs and offshore oil platforms.

The offshore wind power pile foundation mostly adopts a high-performance marine concrete bearing platform and a steel pipe pile foundation. The steel pipe pile mainly comprises a steel pile casing and a concrete pile positioned in the steel pile casing, and is widely applied due to the advantages of enough bearing capacity, relatively simple pile sinking process, small soil discharge amount, good bending resistance and the like. With the rapid construction of offshore wind power plants, the requirements for the stability of offshore wind power pile foundations are constantly improved. Due to the severe offshore operation environment, the complexity of submarine topography and rock stratum, and the influence of construction process and management factors, the phenomenon that surrounding strata are softened, loosened and collapsed in the construction process of the deepwater pile foundation to cause sand leakage in the pile is easily caused, the subsequent construction progress of the pile foundation is seriously hindered, the subsequent construction safety of the pile foundation is also influenced, the bearing capacity of the pile foundation is greatly reduced, the normal and safe operation of the whole offshore wind farm is endangered, and the brought risk loss is unpreferably huge.

At present, the domestic sunk foundation treatment technology is very few in research and application aiming at ocean engineering, mature and feasible technical experience references are lacked, especially, the offshore wind power deep water inclined pile foundation sunk stratum treatment technology is seriously insufficient in experience, few previous application cases only adopt single treatment measures such as drilling and grouting of traditional straight piles and the like, the effect is poor, the problem of ocean stratum sinking cannot be effectively solved, and the safety of follow-up pile foundation construction and wind power plant operation is seriously influenced.

Disclosure of Invention

The invention aims to overcome the defects that the existing marine deep water inclined pile surrounding stratum collapse treatment effect is poor and the subsequent construction and safety requirements cannot be met, and provides a marine deep water inclined pile surrounding soil collapse comprehensive treatment and reinforcement method.

In order to achieve the above purpose of the invention, the following technical scheme is adopted:

a surrounding design arrangement is adopted by taking an original pile foundation as a circle center, inclined hole grouting and pile side high-pressure jet grouting are carried out in a pile and on the pile side, an inclined pile is formed by high-pressure jet grouting on the pile side, and pile surrounding soil is reinforced by overlapping the inclined hole grouting and the jet grouting pile on the outer side of a steel pipe pile foundation. Meanwhile, in a more peripheral subsidence area outside the pile, a mixing pile straight hole is arranged for reinforcement and is meshed with the jet grouting pile, so that a new composite foundation integrating grouting, the jet grouting pile and the mixing pile is formed for reinforcing the soil body around the pile, and the safety and the stability of the offshore deep water inclined pile foundation are effectively enhanced.

A comprehensive treatment and reinforcement method for collapse of stratum around a marine deep-water inclined pile comprises the following steps:

(1) preparation work before treatment: and (3) carrying out geological exploration in the distribution range of the pile foundation, carrying out drilling coring probing before processing, distributing holes after determining the condition of a subsidence area, and measuring, setting and positioning the positions of the drilled holes on the existing pile clamping steel frame platform or the temporary erection construction platform by adopting a measuring instrument.

(2) Grouting in the pile, sealing the pile end of the steel pipe: and (3) drilling a guide hole in the pile by arranging a guide device in the pile in the direction parallel to the steel pipe pile in the pile, guiding a grouting inclined hole, and then putting the grouting pipe into the hole to perform pile end pile bottom grouting.

(3) Pile side high pressure jet grouting: and arranging a guide sleeve in the direction parallel to the steel pipe pile outside the pile, drilling a pilot hole, arranging rotary spraying grouting holes in the direction parallel to the steel pipe pile on the periphery of the steel pipe pile, and performing high-pressure rotary spraying grouting.

(4) And (3) construction of the external stirring pile: after the pile side jet grouting is finished, arranging a straight hole stirring pile in a collapse area on the periphery of the pile foundation to reinforce a stratum which is more peripherally collapsed and is separated from the pile under water.

Further, the rotary spraying grouting piles are distributed in a cross overlapping mode in the step (3) to form a rotary spraying pile group reinforced foundation.

Further, after the reinforcement treatment in the steps (2) to (4), the external grouting reinforcement in the step (5) is carried out: and arranging a guide sleeve in the direction parallel to the steel pipe pile outside the pile, injecting cement slurry into the inclined hole by adopting a perforated pipe multiple grouting process splitting, and supplementing and reinforcing smaller gaps and unfilled dense parts in soil around the pile to enable the pile and a soil body outside the pile to be consolidated into a whole.

Further, the grouting inclined holes in the step (5) and the rotary spraying grouting holes in the step (3) are arranged in a staggered mode.

Further, a pile cap is installed on the top of the pile before grouting in the pile in the step (1), so that grouting in the pile is more compact and solidified.

Further, a guiding and positioning device is arranged in the pile in the step (1), so that the inclination of the grouting pipe in the pile is kept parallel to the inclined pile.

Further, the pile side guide sleeve in the step (3) and the step (5) is fixed by adopting a hoop.

Further, in the step (3), the rotary spraying pressure of the rotary spraying grouting is 10-20 Mpa, and the water-cement ratio is 1.2: 1.0-0.8: 1.0.

furthermore, the inclined hole grouting in the pile and outside the pile, the pile side jet grouting inclined pile and the pile outside stirring pile are combined with the steel pipe pile and the soil body around the steel pipe pile and are crosslinked into an integral composite foundation reinforcing structure.

In summary, due to the adoption of the technical scheme, the invention has the beneficial effects that:

1. the invention provides a comprehensive treatment and reinforcement method for stratum collapse around an offshore deep-water inclined pile foundation, which is used for reinforcing and reinforcing the collapsed stratum around the inclined pile foundation before pile forming in an offshore deep-water environment, effectively ensuring the subsequent safe and smooth construction of the pile foundation, reinforcing the collapsed area of the inclined pile foundation after pile forming, and effectively enhancing the bearing capacity and stability of the inclined pile foundation.

2. The method is adopted for reinforcement treatment to form a new composite foundation integrating grouting, jet grouting and mixing piles, soil cracks around the steel pipe pile are filled, the connection degree of the steel pipe pile and the soil layer around the pile is strengthened, the outer side of the pile and the soil around the pile are effectively and tightly consolidated into a whole, the friction force of the soil around the pile is greatly improved, and the stability of the foundation of the offshore deep-water inclined pile is enhanced. Greatly reducing the follow-up construction period and the economic loss of engineering, and effectively avoiding the occurrence of the potential safety hazard in the later operation.

Drawings

FIG. 1 is a schematic diagram of the situation of stratum collapse around a deep-sea inclined pile in the embodiment.

FIG. 2 is a design diagram of a treatment and reinforcement scheme for the collapse of the stratum around the offshore deep water inclined pile.

FIG. 3 is a construction step diagram of a treatment and reinforcement scheme for the collapse of the stratum around the offshore deep water inclined pile.

Fig. 4 is a schematic view of the effect of the reinforcement treatment according to the embodiment of the present invention.

FIG. 5 is a schematic view of the steel perforated pipe being laid by pile side grouting according to the present invention.

Reference numerals: 1. oblique piles (steel pipe piles); 2. grouting holes; 21. grouting holes in the piles; 22. grouting holes outside the piles; 23. spirally spraying holes; 210. grouting inclined holes in the piles; 220. grouting an outer inclined hole of the pile; 230. carrying out jet grouting pile; 240. stirring straight piles (straight hole stirring piles); 30. a guide sleeve; 31. a connecting member; 32. hooping; 33. a guiding and positioning device in the pile; 40. grouting a floral tube; 41. flower holes; 42. pile end face; 11. a medium-coarse sand layer; 12. completely weathered granite; 13. sandy strongly weathered granite; 14. cracked strongly weathered granite; 15. apoplexy granite; 16. a collapsed region; 17. c40 micro-expansive concrete; 100. temporarily clamping a pile steel platform; 101. averaging the sea level; 102. average surface of the sea bed.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The foundation form to be adopted by the offshore wind farm in a certain place is a high pile cap foundation (including a driving friction pile foundation, a drilling friction pile foundation and a rock-socketed pile foundation). The service life of the basic design is twenty-five years. The high pile cap foundation generally comprises 6-8 inclined piles.

According to the geological survey data, the submarine stratum structure of the offshore wind farm of a certain place comprises a silt layer, silt-containing fine sand, silty clay, a medium-coarse sand layer 11, fully weathered granite 12, sandy strongly weathered granite 13, fractured strongly weathered granite 14, and weathered granite 15 and the like within the drilling depth control range.

During pile forming, in the process of vibrating the steel pipe pile to sink by using a high-frequency vibrating hammer, water is added due to vibration, so that a plurality of steel pipes and surrounding soil layers are loosened and sink downwards, then soil around the pile is gushed into the pile from the outside, and a funnel-shaped sinking area of the soil around the pile from the bottom to the top is formed.

As shown in figure 1, which is a schematic diagram of the situation that soil around the foundation of one inclined pile collapses, in figure 1, one part of an unfinished foundation is shown, the water depth of the pile is about 15m, and during the pile forming process, due to serious collapse, about 300 cubes of dry mixed concrete are cast in the position of the south side of the pile on the positive surface, but the collapse leakage point can not be blocked. The underwater model finds that the collapse area 16 around the pile is large, and an obvious collapse area with the diameter of 6m and the depth of more than 4m is arranged on the south side of the pile; the drilling finds out that a plurality of holes exist in the depth range of 4-12 meters below the mud surface around the pile, an obvious water leakage channel is arranged on the south side of the pile and reaches the bottom of the steel pipe pile, the water leakage channel is in a funnel shape, the depth is 16.50 meters below the sea bottom, and a large amount of sacked broken cloth exists around the water leakage channel. The steel pipe pile 1 can be constructed continuously only by reinforcement.

The collapse point can not be blocked after the collapse area 16 is subjected to hole leading grouting outside the pile in a traditional straight hole mode, and effective reinforcement can not be carried out. And the adoption of the straight hole can not ensure that the soil body around the inclined pile foundation is fully reinforced, and blank areas which can not be reinforced and covered exist.

In the embodiment, a reinforcing structure for stratum collapse around a marine deep-water inclined pile is adopted, a steel pipe inclined pile 1 is used as a center, annular arrangement is adopted, inclined holes are formed in the pile and on the pile side, the inclined holes comprise pile inner inclined hole grouting 210, pile side high-pressure jet grouting pile 230 and pile outer inclined hole grouting 220, and soil around the steel pipe inclined pile foundation is reinforced by overlapping the pile inner inclined hole grouting and the pile outer inclined hole jet grouting pile 230 on the periphery of the steel pipe inclined pile foundation. Meanwhile, the stirring vertical piles 240 are arranged outside the piles, the stirring vertical piles 240 are meshed with each other, and reinforcing treatment is carried out on the peripheral collapse area, so that slurry is combined with soil bodies around the piles through the functions of infiltration, filling, compaction, splitting and the like, a new composite foundation formed by crosslinking the grouting body, the jet grouting piles 230 and the stirring vertical piles 240 into a whole is formed to reinforce the soil bodies around the piles, and the stability of the wind turbine foundation is enhanced.

In this example, qualified p.o.42.5 cement with high corrosion resistance was used, and a witness sampling test was performed before use, and after the test was qualified, the cement was usable, and deteriorated or hardened cement was prohibited from use. During construction, cement slurry is adopted, and the water-cement ratio is 0.8: 1-1: 1. In order to avoid precipitation and pipe blockage, construction is carried out by adopting dilution first and then concentration, and upper dilution and lower concentration.

The comprehensive treatment and reinforcement method for collapse of the offshore deep water inclined pile foundation in the embodiment comprises the following steps:

(1) early exploration probing: the geology within the pile foundation distribution range is explored, the pre-processing drilling coring probing pattern is processed, and the specific conditions of the subsidence area 16 are determined.

(2) Pre-estimating the engineering quantity of a single pile: according to the existing engineering experience, the diameter of the high-pressure jet grouting pile is 1500mm, the reinforcing diameter of the cement mixing pile is 600mm, and the grouting diffusion radius is 1.0 m. It is planned to arrange 4 grouting holes 2 in the pile, 8 or more grouting holes 2, 8 or more high-pressure rotary jet holes 23, and 20 or more cement mixing piles outside the pile, as shown in table 1. The mixing pile reinforces the stratum of the subsidence area 16, the rotary spraying pile 230 and the grouting body are overlapped around the steel pipe pile to reinforce the soil around the pile, so that no blank unreinforced area is ensured, and the soil around the pile is fully treated.

In this embodiment, the number of the grouting holes 2, the number of the jet grouting piles 230 and the number of the mixing piles 240 are related to the range of the single-pile collapse area 16, and the grouting holes 2 need to be encrypted if a gap is too large during construction, so that a blank unreinforced area is ensured, and the aim of forming an integral composite pile foundation with soil around the steel pipe pile is achieved.

TABLE 1 Single pile engineering volume of this example

(3) Manufacturing and installing a temporary pile clamping steel platform 100: the existing pile clamping platform can be utilized for treating the soil around the pile which is not formed into the pile, and a temporary construction platform of a steel truss is erected at the lowest tide water level below the bearing platform for treating the soil around the formed pile.

(4) Hole distribution: and drawing the arrangement diagram of the grouting holes 2, the rotary spraying holes 23 and the mixing pile holes, as shown in figure 2. 4 grouting holes 2 in the steel pipe inclined pile 1, 8 rotary spraying holes 23 and 8 grouting holes 22 are arranged around the steel pipe inclined pile 1 in a circle, and about 20 stirring straight piles 240 are arranged in a collapse area and are numbered uniformly.

(5) Positioning and paying off: and (3) carrying out coordinate positioning on the inclined pile 1 according to a pile foundation design drawing and the condition of the explored collapse area 16 and according to the position of the bottom edge line of the foundation pit, the elevation of the field and the inclination of the inclined pile 1. And (3) setting the drilling position by adopting a measuring instrument to measure and set the line on the existing temporary pile clamping steel platform 100 or a temporary building construction platform according to the design requirement, and if the gap is too large, sealing the grouting hole 2 until the grouting can be ensured to be filled.

(6) Grouting inclined holes 210 in the piles, sealing the pile ends of the steel pipes: and (3) drilling a guide hole in the pile by arranging a guide positioning device 33 in the pile in the direction parallel to the steel pipe pile, guiding a grouting hole 21 in the pile, and then putting the grouting pipe into the hole to perform pile end pile bottom grouting.

4 in-pile grouting holes 21 parallel to the direction of the pile body are led in the pile, in order to avoid the leading holes from touching and damaging the inner wall of the steel pipe pile, the drilled holes are arranged to be 0.3m to 0.5m inside the pile wall, the in-pile grouting holes 21 are symmetrically distributed, and the hole diameter is 110 mm. The deviation between the drilling position and the design position is not more than 10cm, and the inclination of the grouting hole in the pile is not 1% deviation. And accurately recording the drilling depth, and comparing the drilling depth with a pile sinking record report. And (3) preparing cement paste with a water-cement ratio of 1:0.8, grouting the bottom of the pile at the end of the pile, and filling the interior of the pile to a certain height (more than 2.0 m). The method aims to fill the gaps around the pile and seal the pile bottom of the steel pipe inclined pile 1, so as to block the flowability of seawater caused by tide at the pile bottom, and avoid the influence on the effects of subsequent stirring pile and grouting due to the slurry leakage in the pile during subsequent grouting. And simultaneously, the pile inner and pile outer reinforcing structures at the pile end are combined to form an integral overlapping structure. If the gap is too large in the construction process, the number of the grouting holes 2 needs to be increased until the grouting can be ensured.

Preferably, a pile cap (not shown) is installed on the top of the pile before grouting to make the grouting 210 more compact and solid.

Preferably, the in-pile guide positioning device 33 is installed so that the inclination of the in-pile grouting pipe is maintained parallel to the batter pile 1. Guiding orientation device 33 is wooden guide support plate in the stake in this embodiment, opens 4 injected hole 2 in the guide support plate, and the slip casting pipe passes the hole and transfers, transfers to opening after stake terminal surface 42 positions and bores the guiding hole to about 0.5m below the stake end. The purpose of pile end and pile bottom grouting is to fill the gaps around the pile to seal the pile bottom, prevent the subsequent pile side grouting from leaking slurry in the pile, and simultaneously combine the pile inner part and the pile outer grouting 220 reinforcing structure at the pile end to form an integral foundation structure.

(7) Grouting by rotary spraying at the side of the pile: and arranging a guide sleeve 30 outside the pile in a direction parallel to the steel pipe pile, drilling a pilot hole by using the guide sleeve 30, drilling rotary spray holes 23 in parallel on the periphery of the steel pipe pile, and performing high-pressure rotary spray grouting.

A pile-side guide sleeve 30 is provided in parallel outside the steel pipe pile. The position and the inclination of the pile side guide sleeve 30 are adjusted according to the inclination of the pile foundation, so that the pile side guide sleeve 30 and the steel pipe inclined pile 1 are kept parallel.

In this embodiment, the pile-side guide sleeve 30 is fixed by means of a hoop 32. Steel pipe encircling buckles are arranged at intervals of 6m in the longitudinal direction of the inclined pile 1, and each buckle is provided with 6 guide sleeves 30. The diameter of the installed pile side guide sleeve is 30 mm, and the distance from the center to the edge of the pipe pile is 0.4 m. The guide sleeve 30 is inclined in accordance with the inclination of the batter pile 1, and the inner wall of the guide sleeve 30 must be smooth. The guide sleeve 30 is inserted into the mud surface through the sea bed surface to a certain depth and is stable, the installation of the process is difficult, and a diver needs to be matched for installation when necessary. Other mounting means, such as sliding rails, slot fixing, sleeve mounting, etc., may also be employed for the pile-side guide sleeve 30. After the grouting is completed, the pile-side guide sleeve 30 can be removed and reused. The pile side guide sleeve 30 has the effects of stabilizing and protecting the subsequent rotary spraying and grouting operation, and avoiding the construction difficulty caused by the buoyancy and scouring of seawater on the subsequent grouting; and secondly, the inclination of rotary spraying and grouting is effectively controlled to be parallel to the inclined pile, and inclined hole rotary spraying and inclined hole grouting operation is guaranteed.

The pile side guide sleeve 30 and the steel pipe inclined pile 1 are kept parallel to carry out inclined hole reinforcing treatment, and the purpose is to ensure that the soil around the steel pipe pile foundation is sufficiently reinforced without blank areas; if adopt traditional perpendicular straight hole, on the one hand need punch according to the different degree of depth layering and consolidate and increase and draw hole work load, consume the cycle length, on the other hand can not ensure that the soil body around the steel-pipe pile is fully consolidated, has the blank area that can't consolidate the cover, just also can't ensure the quality of consolidating the processing.

After the pile side guide sleeve 30 is installed, the platform is cleaned to install the drilling machine, and the inclination of the drilling machine is adjusted (the error is less than 1.0%). The method comprises the steps of guiding 8 rotary spraying holes 23 parallel to the direction of a pile body by utilizing a pile side guide sleeve 30, symmetrically distributing the inclined steel pipe pile 1 by taking the inclined steel pipe pile 1 as the center, arranging the drill holes at 0.5-0.8 m outside the pile wall, avoiding the guide holes from touching and damaging the outer wall of the steel pipe pile, and enabling the rotary spraying diameter to be 1200-1600 mm, wherein the number of the rotary spraying piles 230 is enough, so that cement slurry is poured into the top, the bottom and the side part of soil around the steel pipe pile within the range of 1-2 m, and no blank unreinforced area exists. And accurately recording the drilling depth, and comparing the drilling depth with a pile sinking record report. Before the construction of the drilling machine, low-pressure trial spraying is firstly carried out on the platform, and after the trial running of the drilling machine is normal, the pilot hole drilling is started. And after the pilot hole is drilled, inserting a rotary spray pipe, performing test spraying, and after the construction technical parameters are determined, putting the spray pipe to the bottom of the hole. In order to improve the quality of the bottom end of the pile, the drilling rod guniting rotary spraying time is properly increased within 1.0m of the bottom of the pile. After the injection grouting pipe is inserted into the designed depth, the high-pressure slurry pump pressurizes to 15-20 MPa, and then performs rotary spraying from bottom to top, and simultaneously cleans and discharges slurry. In the rotary spraying lifting process, the rotary spraying parameters are continuously adjusted according to different positions. Finally forming the jet grouting pile 230.

Preferably, an inner sleeve follow-up treatment is used during the hole leading process to avoid the influence of hole re-collapse.

In this embodiment, the deviation between the drilling position and the design position is not larger than 10 cm. The aperture of the high-pressure jet grouting inclined hole is 110mm, the hole inclination is less than or equal to 1%, and the hole depth is not less than at least 1m below the pile end of the steel pipe pile. The water-cement ratio is 1.2: 1.0-0.8: 1.0, and 10-20 Mpa of rotary spraying pressure. And in the rotary spraying lifting process, the rotary spraying parameters are continuously adjusted according to different positions.

Table 2 technical parameter table of high-pressure injection grouting construction process in this embodiment

(8) And (3) construction of the external stirring pile: after the pile side jet grouting is finished, the collapse area 16 on the periphery of the pile foundation is provided with the straight hole stirring pile 240, and the collapse area on the periphery of the underwater pile is reinforced. The plurality of straight hole stirring piles 240 are meshed with each other, the straight hole stirring piles 240 are cross-linked with the jet grouting piles 230 on the sides of the piles to completely cover the soil area around the piles, no unreinforced blank area exists, and a new integral composite foundation is formed to reinforce the soil mass around the piles.

Cleaning the platform and installing the drilling machine, and adjusting the inclination of the drilling machine (the error is less than 1.0%). And after the drilling machine is normally operated, stirring drilling is started, and the drilling depth is recorded in detail in the drilling process. And (3) carrying out underwater stratum strengthening treatment on the straight hole stirring piles 240 in the collapse area 16 on the periphery of the pile foundation.

In this embodiment, the peripheral collapse area 16 of the steel pipe spud 1 is treated by more than 20 straight hole stirring piles 240. The diameter of the straight hole stirring pile 240 is 600mm, and the hole depth is not less than 0.1m on the bottom of the pile. The water-cement ratio is 1.1: 1.0-0.8: 1.0, and the pressure of the stirring paddle is 0.1-0.2 Mpa.

Table 3 technical parameter table for construction process of external mixing pile in this embodiment

(9) Checking the gap and touching the weak position.

(10) Grouting outside the pile for reinforcement: the guide sleeve 30 is arranged on the outer side of the pile in the direction parallel to the steel pipe pile, the grout is injected by adopting a grouting perforated pipe 40 for multiple times of grouting after the inclined hole is led, and small gaps and unfilled dense parts in soil around the pile are supplemented and reinforced, so that the pile and soil outside the pile are consolidated into a whole, and the reinforcement is ensured to be sufficient.

In the embodiment, inclined holes are drilled for grouting reinforcement, and cement single slurry is poured by adopting a grouting floral tube 40 grouting process after drilling. Cleaning a platform, installing a drilling machine in the middle of 2 rotary spraying holes 23, adjusting the inclination of the drilling machine (the error is less than 1.0 percent), and leading 8 inclined grouting holes 22 parallel to the direction of the pile body. And a stirrer and a slurry pump are debugged before drilling, so that the equipment can normally run. And (3) drilling by using an XY-300 type drilling machine, and drilling by using a mud wall protection method, wherein the hole diameter of the drilled hole is 110 mm. The number of drill rod sections is well recorded in the drilling process, and the accuracy of the drilling depth is ensured. And the position of the void is recorded. FIG. 5 is a schematic view of a pile side grouting lower grouting pipe according to the present invention. When the treatment depth range is reached, the speed is slowed down, and the drilling conditions are carefully observed, such as the presence or absence of slurry leakage, the presence or absence of fillers (necessary coring), and the like. Mounting principle of the perforated pipe 40: the flower tube 40 (the caliber is 50mm) is completely arranged at the deeper section, the hole bottom and the hole position are arranged at the opening of the flower tube 40, and the opening is about 30cm higher than the pile clamping platform. In the embodiment, the pile outer grouting 220 is reinforced by multiple pressurization splitting grouting, and the hole forming and cleaning are carried out before grouting, so that the condition that the cleaning solution becomes clear is met.

(11) Moving to the next construction pile position and repeating the steps. And 7-14 days after grouting, carrying out spot check according to the number of pile holes, and carrying out a compression test and a standard penetration test. Through detection, the soil around the pile is compactly and stably filled, does not leak water, and has better reinforcing effect.

In the steps (6) - (7) and (10), inclined hole drilling is a key process for constructing a prerequisite foundation and ensuring sufficient collapse and reinforcement of the stratum around the pile by subsequent reinforcement measures. According to the invention, the collapse area 16 of the offshore deep-water inclined pile foundation is comprehensively treated and reinforced by various means through the construction steps, so that the problem of pile foundation collapse caused by soil loosening and loss due to construction vibration is solved, the soil body around the pile forms an integral new composite foundation, the collapse treatment effect on the offshore deep-water inclined pile foundation is obvious, and the subsequent construction of the offshore wind power plant pile foundation is smoothly carried out. Compared with the traditional straight hole treatment mode, the construction cost is low, and the period is short.

While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should not be limited to the embodiments disclosed, but includes various alternatives and modifications without departing from the present invention, which are encompassed by the claims.

Claims

1. A comprehensive treatment and reinforcement method for stratum collapse around an offshore deep water inclined pile is characterized in that the inclined pile is a steel pipe pile foundation and comprises the following steps:

2. The comprehensive treatment and reinforcement method for stratum collapse around the offshore deep water inclined pile according to claim 1, characterized by comprising the following steps: and (4) the rotary spraying grouting piles are distributed in a crossed and overlapped mode in the step (3) to form a rotary spraying pile group reinforced foundation.

3. The comprehensive treatment and reinforcement method for stratum collapse around the offshore deep water inclined pile according to claim 1, characterized by comprising the following steps: and (3) performing grouting reinforcement outside the pile in the step (5) after reinforcement treatment in the step (2) and the step (4): and arranging a guide sleeve in the direction parallel to the steel pipe pile outside the pile, injecting cement slurry into the inclined hole by adopting a perforated pipe multiple grouting process splitting, and supplementing and reinforcing smaller gaps and unfilled dense parts in soil around the pile to enable the pile and a soil body outside the pile to be consolidated into a whole.

4. The comprehensive treatment and reinforcement method for stratum collapse around offshore deep water inclined pile according to claim 3, characterized by comprising the following steps: and (5) arranging the grouting inclined holes and the rotary spraying grouting holes in the step (3) in a staggered manner.

5. The comprehensive treatment and reinforcement method for stratum collapse around the offshore deep water inclined pile according to claim 1, characterized by comprising the following steps: and (2) installing a pile cap sealing steel pipe pile on the pile top before grouting in the pile in the step (1), so that grouting in the pile is more compact and solidified.

6. The comprehensive treatment and reinforcement method for foundation collapse of the offshore deep water inclined pile according to claim 1, characterized by comprising the following steps of: and (3) arranging a guiding and positioning device in the pile in the step (1) to ensure that the inclination of the grouting pipe in the pile is kept parallel to the inclined pile.

7. The comprehensive treatment and reinforcement method for foundation collapse of the offshore deep water inclined pile according to claim 1 or 3, characterized by comprising the following steps of: and (5) fixing the pile side guide sleeve by adopting a hoop.

8. The comprehensive treatment and reinforcement method for stratum collapse around offshore deep water inclined pile according to claim 1 or 2, characterized by comprising the following steps: in the step (3), the rotary spraying pressure of the rotary spraying grouting is 10-20 Mpa, and the water-cement ratio is 1.2: 1.0-0.8: 1.0.

the comprehensive treatment and reinforcement method for stratum collapse around the offshore deep water inclined pile according to claim 1, characterized by comprising the following steps: and grouting inclined holes in and outside the piles, jet grouting inclined piles at the sides of the piles, combining the stirring piles outside the piles with the steel pipe piles and soil around the piles, and crosslinking to form an integral composite foundation reinforcing structure.